public static ReadOnlySequence <byte> Serialize(BaseCommand command, MessageMetadata metadata, ReadOnlySequence <byte> payload)
{
var commandBytes = Serialize <BaseCommand>(command);
var commandSizeBytes = ToBigEndianBytes((uint)commandBytes.Length);
var metadataBytes = Serialize(metadata);
var metadataSizeBytes = ToBigEndianBytes((uint)metadataBytes.Length);
var sb = new SequenceBuilder <byte>().Append(metadataSizeBytes).Append(metadataBytes).Append(payload);
var checksum = Crc32C.Calculate(sb.Build());
return(sb.Prepend(ToBigEndianBytes(checksum))
.Prepend(Constants.MagicNumber)
.Prepend(commandBytes)
.Prepend(commandSizeBytes)
.Prepend(ToBigEndianBytes((uint)sb.Length))
.Build());
}
private async ValueTask <bool> Validate(MessagePackage messagePackage)
{
var magicNumberMatches = messagePackage.Data.StartsWith(Constants.MagicNumber);
var expectedChecksum = messagePackage.Data.ReadUInt32(2, true);
var actualChecksum = Crc32C.Calculate(messagePackage.Data.Slice(6));
if (!magicNumberMatches || expectedChecksum != actualChecksum)
{
var ack = new CommandAck
{
Type = CommandAck.AckType.Individual,
validation_error = CommandAck.ValidationError.ChecksumMismatch
};
ack.MessageIds.Add(messagePackage.MessageId);
await Send(ack);
return(false);
}
return(true);
}